CN114502447A

CN114502447A - Auxiliary thrust system for carriages or loads moving generally on wheels

Info

Publication number: CN114502447A
Application number: CN202080063401.5A
Authority: CN
Inventors: D·卡塔内奥; G·邦凡蒂
Original assignee: Ruishengnuo Manufacturing Co ltd
Current assignee: Ruishengnuo Manufacturing Co ltd
Priority date: 2019-10-03
Filing date: 2020-09-11
Publication date: 2022-05-13
Anticipated expiration: 2040-09-11
Also published as: WO2021064496A1; EP4037925A1; KR20220077121A; US20220332358A1; CN114502447B; US11753059B2

Abstract

Auxiliary thrust system for a wheeled carrier (1), comprising a base (6), a first steering wheel (2) and a second steering wheel (3) being mounted to the base (6), the first steering wheel (2) and the second steering wheel (3) being connected to the base (6) so as to be rotatable about respective axes (7, 8) perpendicular to the base (6); the first drive wheel (9) and the second drive wheel (10) are mounted to the base (6) and they are rotated by at least one gear motor unit (13, 15; 14, 16; 48, 49) which drives the first drive wheel (9) via a first magnetic coupling (22, 23, 24, 25, 26) and the second drive wheel (10) via a second magnetic coupling (32, 33, 34, 35, 36).

Description

Auxiliary thrust system for carriages or loads moving generally on wheels

Technical Field

The present invention relates to an auxiliary thrust system for moving loads, for example for moving food carriers or carriers in general having a load surface on which a load to be moved can be arranged.

Background

From CN 106428301 an auxiliary pulling device for a mine carriage is known, which comprises a motor mounted to the rotational shaft of at least one wheel of the mine carriage. The rotational axis of the wheel is directly connected to the motor shaft. Preferably, a respective motor is applied to a pair of opposed wheels of the carriage. The one or more motors have sufficient power to move the carriage so that by activating the one or more motors, the carriage can be used without the need for thrust intervention by the carriage operator. Since the motor is applied directly to the wheel axle, the motor torque and motor power required to move the carriage is high, making the traction device expensive.

JP S63215459 discloses a carriage for transporting a load, the carriage comprising: a base for placing a load to be transported, a grip that an operator grips to apply a force to the carriage, and a force sensor arranged between the base and the grip. The carriage also includes a pair of steering wheels and a pair of drive wheels. The steering wheel is driven by a first motor fixed to the base of the carriage and is connected to a steering system by which the direction of movement of the steering wheel can be changed; the drive wheel is driven by a second motor mounted to a shaft of the drive wheel. The first motor and the second motor are controlled by a control unit which controls driving the first motor and the second motor to steer the steering wheel (if necessary) according to the intensity and direction of the force applied to the carriage by the operator, and to advance or retreat the carriage by canceling the force applied to the grip by the operator. The drive system for the carriage is very complex and expensive.

CN 205737609U discloses a light electric vehicle for the action of moving a load, which comprises a frame, a motor, a controller and a battery. The motor and the battery are respectively connected with the controller. The motor includes a left motor and a right motor, each mounted to the axle of one of the rear wheels of the carriage.

The control device comprises a start/stop switch, a control mode selection switch and a backward-forward selection switch.

The user selects the operating mode of the carriage by means of a start/stop switch, a control mode selection switch and a reverse/forward selection switch. Upon detection of the control signal, the microcontroller sends a control signal to an electronic unit controlling the driving of the motor, enabling the carriage to be activated.

The start/stop switch is used to transmit start/stop signals, the control mode select switch is used to transmit push/command control mode signals, and the back/forward select switch is used to transmit forward and back signals. After activation of the above-mentioned switches, the user is helped in all the carriage moving steps, but the control of the motor comprising the three switches complicates the operation of the carriage.

US 6276219 discloses a transport carriage comprising a load positioning portion and a portion in which the assembly of carriage drives is positioned. The drive wheels are driven by an electric motor, which may be an electric motor powered by a rechargeable battery, for example. The bracket is also provided with a steering rod which can rotate around the shaft. At the free end of the steering rod, a grip is provided, which is provided with an operating button to raise and lower the steering rod.

The steering rod is also provided with a sensor device that measures the force with which the operator pulls or pushes the carriage. The sensor device transmits an output signal, which is transmitted to the feedback control unit. The feedback control unit contains software associated with the driver assembly. The feedback control unit processes the signal received from the sensor device and converts it into a drive signal, which is sent to the electric motor, thereby applying a force (torque) to the wheel connected to the electric motor. The feedback control unit is able to compensate the operator's force by driving the motor such that the force applied to the steering rod and measured by the sensor means is substantially zero or very small.

In an emergency situation, for example in the case of a reversal of the direction of movement, a brake can be activated which brings the carriage to an immediate stop.

In this case, the drive system of the carriage is also complex and expensive.

Furthermore, the carriage disclosed in the above-mentioned document also has the drawback that, once the motor or motors connected to the wheels of the carriage are activated, if the operator for any reason loses control of the carriage, the carriage can move autonomously, thus posing a danger to people in the vicinity of the carriage.

Disclosure of Invention

It is an object of the present invention to provide an auxiliary thrust system for loads moving on wheels that is simple and inexpensive to manufacture.

Another object of the present invention is to provide an auxiliary thrust system which is easy and safe to use for the operator who must move the load placed on the carriage.

The object of the invention is achieved by an auxiliary thrust system according to claim 1.

In accordance with the present invention, an easily manufactured and low cost supplemental thrust system is provided that assists the operator in moving the load on the carriage, significantly reducing the effort required by the operator to move the carriage.

The system according to the invention is simple to use, since it does not require complex operations by the operator to activate or deactivate the system.

Furthermore, the system is safe, because the carriage cannot move autonomously, for example when the operator loses grip on the carriage, because the push exerted by the system on the carriage is not sufficient to move the carriage autonomously (i.e. without the push of the operator), but only serves to reduce the effort required by the operator to move the carriage.

Drawings

Other features and advantages of the present invention will be derived from the following description with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a food carriage to which the auxiliary thrust system according to the present invention is applied;

FIG. 2 is a perspective bottom view of the bracket of FIG. 1;

FIG. 3 is an enlarged detail of FIG. 2;

FIG. 4 is a front view of the first drive wheel of FIG. 1 with an auxiliary thrust system bracket according to the present invention;

FIG. 5 is an exploded view of the first drive wheel of FIG. 4, with an auxiliary thrust system according to the present invention;

FIG. 6 is a partially exploded perspective view of the first drive wheel of FIG. 4, with an auxiliary thrust system in accordance with the present invention;

FIG. 7 is a partially exploded front elevational view of the first drive wheel of FIG. 4, with an auxiliary thrust system in accordance with the present invention;

FIG. 8 is a view similar to FIG. 7, partially sectioned along line A-A of FIG. 7;

FIG. 9 is a front view of a second drive wheel of the carriage of FIG. 1, with an auxiliary thrust system according to the present invention;

FIG. 10 is an exploded view of the second drive wheel of FIG. 9, with an auxiliary thrust system according to the present invention;

FIG. 11 is a partially exploded perspective view of the second drive wheel of FIG. 9, with an auxiliary thrust system according to the present invention;

FIG. 12 is a partially exploded front elevational view of the second drive wheel of FIG. 9, with an auxiliary thrust system in accordance with the present invention;

FIG. 13 is a view similar to FIG. 12, partially sectioned along line B-B of FIG. 12;

figures 14 and 15 show a version of the auxiliary thrust system according to the invention applied to a carriage similar to that of figure 1;

figures 16 to 20 show a command system enabling an operator to start and stop the auxiliary thrust system according to the invention.

Detailed Description

In fig. 1 to 3, as a non-limiting example, a food carriage 1 provided with an auxiliary thrust system according to the present invention is shown.

The carriage 1 comprises a first direction wheel 2 and a second direction wheel 3 for enabling the carriage 1 to change direction during movement.

The first direction wheel 2 is mounted to a first support 4 connected to a base 6 of the carriage 1 so as to be rotatable about a first axis of rotation 7 perpendicular to the base 6.

The second direction wheel 3 is mounted to a second support 5 connected to a base 6 of the carriage 1 so as to be rotatable about a second axis of rotation 8 perpendicular to the base 6.

The carrier 1 further comprises a first drive wheel 9 and a second drive wheel 10, the first drive wheel 9 being mounted to a third support 11 fixedly mounted to the base 6 of the carrier 1, and the second drive wheel 10 being mounted to a fourth support 12 also fixedly mounted to the base 6.

With reference to fig. 4 to 8, an auxiliary thrust system according to the present invention applied to the first driving wheel 9 is now disclosed.

The auxiliary thrust system comprises a first

gear motor unit

13, 15 designed to drive the first driving wheel 9 and constituted by a first motor 13 and a first gear reducer unit 15. The first

gear motor unit

13, 15 is fixed to the third support 11 by a plurality of screws 30.

The first

gear motor unit

13, 15 transmits motion to the first drive wheel 9 via a first magnetic coupling, as will be disclosed below.

The first gear reducer unit 15 has a first output shaft 17, the first output shaft 17 being supported on the third support 11 by a first pair of

bearings

18 and 19.

A first disc 22 made of an electrically conductive metal material, for example aluminium, and a second disc 23 also made of an electrically conductive metal material, for example aluminium, are wedged (key) against the first output shaft 17 by means of respective

first keys

20, 21. On the first output shaft 17, between the first disc 22 and the second disc 23, the first driving wheel 9 is arranged by means of a second pair of

bearings

28, 29 to rotate freely on the first output shaft 17.

The first disk 22 is inserted with clearance in a first seat 45 (figure 8) obtained in the first drive wheel 9, so as to be able to rotate with respect to the first drive wheel 9.

The second disc 23 is inserted with clearance in a second seat 24 obtained in the first drive wheel 9, opposite the first seat 45, so as to be able to rotate with respect to the first drive wheel 9.

The first drive wheel 9 is provided with a plurality of first housings 27, into which first set of permanent magnets 25 facing the first disk 22 are inserted, and into which first housings 27 second set of permanent magnets 26 facing the second disk 23 are inserted.

The first disc 22, the second disc 23, the first set of permanent magnets 25 and the second set of permanent magnets 26 constitute a first magnetic coupling for transmitting motion from the first

gear motor unit

13, 15 to the first drive wheel 9.

When the first motor 13 is driven, the first motor 13 rotates the output shaft 17 of the first gear reducer unit 15, which causes the first and

second disks

22 and 23 to rotate in the magnetic field generated by the first and second sets of

permanent magnets

25 and 26.

The rotation of the first disk 22 and the second disk 23 within the magnetic field determines the eddy currents formed in the first disk 22 and the second disk 23. The magnetic field generated by the eddy currents interacts with the magnetic fields of the first and second sets of

permanent magnets

25, 26, causing the first drive wheel 9 to rotate and generate a thrust on the carriage that reduces the thrust required by the operator to move the carriage.

With reference to fig. 9 to 13, an auxiliary thrust system according to the present invention applied to the second driving wheel 10 is disclosed, which is substantially identical to the auxiliary thrust system applied to the first driving wheel 9.

The auxiliary thrust system applied to the second driving wheel 10 comprises a

second gearmotor unit

14, 16 designed to drive the second driving wheel 10 and constituted by a second electric motor 14 and a second gear reducer unit 16. The second

gear motor unit

14, 16 is fixed to the fourth support 12 by a plurality of screws 42.

The second geared

motor units

14, 16 transmit motion to the second drive wheel 10 via a second magnetic coupling which is substantially identical to that previously disclosed in relation to the first drive wheel 9.

The second gear reducer unit 16 has a second output shaft 31, the second output shaft 31 being supported on the fourth support 12 by a third pair of

bearings

38 and 39.

A third plate 32 made of an electrically conductive metal material (for example aluminium) and a fourth plate 33 also made of an electrically conductive metal material (for example aluminium) are wedged against the second output shaft 31 by means of respective

second keys

40, 41. On the second output shaft 31 and between the third disc 32 and the fourth disc 33, the second driving wheel 10 is arranged by a fourth pair of

bearings

43, 44 to rotate freely on the second output shaft 31.

The third disc 32 is inserted with clearance in a third seat 46 obtained in the second driving wheel 10, so as to be able to rotate with respect to the first driving wheel 10.

The fourth disc 33 is inserted with clearance in a fourth seat 34 obtained in the second drive wheel 10, located opposite the third seat 46, so as to be able to rotate with respect to the second drive wheel 10.

The second driving wheel 10 is provided with a plurality of second housings 37, and a third group of permanent magnets 35 facing the third disk 32 and a fourth group of permanent magnets 36 facing the fourth disk 33 are inserted into the second housings 37.

The third disc 32, the fourth disc 33, the third set of permanent magnets 35 and the fourth set of permanent magnets 36 constitute a second magnetic coupling for transmitting motion from the second

gear motor unit

14, 16 to the second drive wheel 10.

When the second electric motor 14 is driven, the second gear reducer unit 16 rotates the second output shaft 31, which rotates the third and

fourth disks

32, 33 in the magnetic field generated by the third and fourth sets of

permanent magnets

35, 36.

The rotation of the third disk 32 and the fourth disk 33 within the magnetic field determines the eddy currents formed in the third disk 32 and the fourth disk 33. The magnetic field generated by the eddy currents interacts with the magnetic fields of the third and fourth sets of

permanent magnets

35, 36 causing the second drive wheel 10 to rotate and generate a thrust on the carriage which reduces the thrust required by the operator to move the carriage.

In fig. 14 and 15, a variant of the auxiliary thrust system according to the invention is shown, purely by way of non-limiting example, applied to a food carriage 1.

In the carrier 1, in this solution, the first 9 and second 10 drive wheels are mounted to rotate freely at opposite ends of the shaft 47. The shaft 47 is supported on the base 6 of the carriage 1 by the first support 11 and the second support 12.

The auxiliary thrust system according to the invention comprises a single gear-motor unit 48, 49, which is constituted by a third electric motor 48 and a third gear-reducer unit 49, the third electric motor unit 48 being powered by a battery provided by the carriage 1, the output shaft of the third gear-reducer unit 49 being connected (for example by means of a joint) to the shaft 47. The motion is transmitted to the

driving wheels

9 and 10 by means of respective magnetic couplings, which are identical to those disclosed (refer to the solution of the thrust system according to the invention shown in figures 1 to 13). Reference is therefore made to the description of the auxiliary thrust system relating to the solution of the invention shown in figures 1 to 13, with regard to the constructional details and the operation of the auxiliary thrust system applied to the

driving wheels

9 and 10.

In fig. 16 to 20, a control system is shown which enables the operator to start and stop the auxiliary thrust system according to the invention, also to select the direction of rotation of the first and

second motors

13 and 14 or the direction of rotation of the third motor 48.

The control system comprises a handle 51, at the front wall 52 of the carrier 1, the handle 51 being fixed to a frame 55 of the carrier 1, and a control panel 50 may be mounted on the front wall 52, for example in case the carrier is used for dispensing hot meals or chilled foods.

The handle 51 includes a grip 56, and a first plate 57 and a second plate 58 arranged perpendicular to the grip 56 are fixed to ends of the grip 56.

The first plate 57 is provided with a first seat 67, the first seat 67 being able to couple with a first support 53 fixed to the frame 55, the second plate 58 is provided with a second seat 68, the second seat 68 being able to couple with a second support 54 fixed to the frame 55. The first support 53 and the second support 54 are used to fix the handle 51 to the frame 55 of the bracket 1. This fixing is achieved by means of a first pin 59 and a second pin 61, the first pin 59 being inserted in a hole 66 of the first plate 57 and in a corresponding hole 60 of the first support, the second pin 61 being inserted in a corresponding hole of the second plate 58 and in a corresponding hole of the second support 54 (not visible in the figures).

On the first support 53, there are fixed a first switch (for example, a microswitch) 62 and a second switch (for example, a microswitch) 63, which are normally open, for commanding the start of the first motor 13 and the second motor 14, or the start of the third motor 48, respectively, in a first rotation direction and in a second rotation direction opposite to the first rotation direction.

In the first seat 67, a first inclined plane 69 and a second inclined plane 70 are provided, the first inclined plane 69 being designed to interact with the first microswitch 62 and the second inclined plane 70 being designed to interact with the second microswitch 63. A similar inclined plane (not visible in the figures) is provided in the second seat 68.

The first and

second springs

62, 63 are further mounted to the first support 53, while the third and fourth springs (not visible in the figures) are mounted to the second support 54. The spring is held in compression by inclined planes provided in the first and

second seats

67, 68 to return the handle 56 to a neutral position (visible in fig. 16) when the operator stops applying force to the handle 51, as will be explained below.

When the operator has to operate the carriage 1, the operator activates the third motor 48 or the first motor 13 and the second motor 14 by acting on the handle 51. If the operator applies a thrust on the handle 51 to the wall 52 of the carriage, starting from the neutral position shown in fig. 16, in the direction of the arrow F4 in fig. 20, the handle 51 will rotate about the

pins

59 and 61 in the first rotation direction F2, so that the second inclined plane 70 presses on the second switch 63, turning the second switch 63 to the closed position to activate the first motor 13 and the second motor 14, or the third motor 48 (in a rotation direction coinciding, for example, with the forward movement of the carriage 1). On the other hand, if the operator exerts a traction force on the handle 51 in the direction of the arrow F3 in fig. 20 to move away from the wall 52 of the carriage, the handle 51 rotates about the

pins

59 and 61 in a second rotation direction F1 opposite to the first rotation direction F2, so that the first inclined plane 69 presses on the first switch 62, turning the first switch 62 to the closed position to activate the first motor 13 and the second motor 14 or the third motor 48 (in a rotation direction coinciding, for example, with the backward movement of the carriage 1). The first and

second motors

13 and 14, or the third motor 48, will remain running as long as the operator continues to exert a pushing or pulling force on the handle 51.

If the operator stops exerting a pushing or pulling force on the handle 51, the first spring 64, the second spring 65, the third spring and the fourth spring, as previously described, return the handle 51 to the neutral position in which the handle 51 does not interact with the

micro-switches

62, 63, the

micro-switches

62, 63 thus returning to the open position, causing the first motor 13 and the second motor 14 or the third motor 48 to stop. This has the significant advantage of completely eliminating the risk that the carriage may move autonomously without being controlled by the operator, thus ensuring maximum safety in use of the auxiliary thrust system according to the invention.

Alternatively, the starting and stopping of the first motor 13 and the second motor 14 or the third motor 48 and the selection of the rotation direction thereof may be performed by arranging control buttons at positions ergonomically adapted to the operator (depending on the shape and structure of the carriage 1 so that the operator can conveniently access the control buttons).

It should be noted that in fig. 18, the

microswitches

62 and 63, the first spring 64 and the second spring 65 are shown inside the first seat 67, i.e. in the positions they are in when the handle 51 is mounted to the

supports

53, 54.

Since the

aluminum discs

22, 23; 32. 33 and

permanent magnets

25, 26; 35. 36, a torque is generated on the

drive wheels

9, 10, which facilitates the pushing of the carriage by the operator.

In order to brake the carriage, it is sufficient for the operator to reverse the rotation direction of the first motor 13 and the second motor 14 or the third motor 48.

It should be noted that the third motor 48 or the first motor 13 and the second motor 14 are sized to provide a drive torque insufficient to independently move the carriage, but to assist operator propulsion. Furthermore, this function makes the handling of the carriage simpler and safer, as it helps to eliminate the risk that the carriage can move autonomously without being pushed by the operator. Advantageously, the movement of the driving wheel is transmitted by a magnetic coupling, thus not using any mechanical elements susceptible to wear.

Furthermore, when the auxiliary thrust system is turned off, the driving wheels can rotate freely without any friction generated by the system. This has the significant advantage that the carriage can be easily moved anyway when the energy source supplying the auxiliary thrust system is exhausted, without having to resort to the mechanical release means that must be present in the systems disclosed in the above-mentioned prior art documents.

Furthermore, the system according to the invention does not require a differential (differential) u, which is normally used in motorized systems and is necessary for modifying the rotation speed of the driving wheels on the curve. In the auxiliary thrust system according to the present invention, the speed between one driving wheel and the other is automatically changed due to the magnetic coupling between the third electric motor 48 or the first electric motor 13 and the second electric motor 14 and the

driving wheels

9, 10 of the carriage.

The invention has been disclosed with reference to food carriages, but it must be understood that the auxiliary thrust system according to the invention can be used with any type of carriage for moving loads.

Claims

1. Auxiliary thrust system for a wheeled carrier (1), wherein the carrier (1) comprises a base (6) on which a first direction wheel (2) and a second direction wheel (3) are mounted, the first direction wheel (2) and the second direction wheel (3) being connected to the base (6) by respective supports (4, 5) and being rotatable relative to the base (6) about respective axes (7, 8) perpendicular to the base (6), wherein the first drive wheel (9) and the second drive wheel (10) are further mounted to the base (6) and are rotated by at least one gear motor unit (13, 15; 14, 16; 48, 49), wherein the at least one gear motor unit drives the first drive wheel (9) by means of a first magnetic coupling (22, 23, 24, 25) and the second drive wheel (10) by means of a second magnetic coupling (32, 33, 34, 35), characterized in that said first magnetic coupling (22, 23, 24, 25) comprises a first disc (22) made of electrically conductive material and a second disc (23) made of electrically conductive material, the first disc (22) and the second disc (23) being mounted to a first output shaft (17) of the first gear motor unit (13, 15), a first set of permanent magnets (25) and a second set of permanent magnets (26) being inserted in first seats (27) provided with the respective first driving wheel (9), wherein the first driving wheel (9) is arranged between the first disc (22) and the second disc (23) on the first output shaft (17) so as to rotate freely with respect to the first output shaft, wherein the first disc (22) is inserted with clearance in a first seat (45) obtained in the first driving wheel (9) and faces the first set of permanent magnets (25), wherein the second disc (23) is inserted with clearance in a second seat (45) obtained in the first driving wheel (9), A second seat (24) located opposite the first seat (45) and facing the second set of permanent magnets (26), and characterized in that the second magnetic coupling (32, 33, 34, 35) comprises a third disc (32) made of electrically conductive material and a fourth disc (33) made of electrically conductive material, the third disc (32) and the fourth disc (33) being mounted to the second output shaft (31) of the second gear motor unit (14, 16), the third set of permanent magnets (35) and the fourth set of permanent magnets (36) being inserted in a second seat (37) provided to the respective second driving wheel (10), wherein the second driving wheel (10) is arranged between the third disc (32) and the fourth disc (33) on the second output shaft (31) and is free to rotate with respect to the second output shaft, wherein the third disc (32) is inserted with clearance in a third seat (46) obtained in the second driving wheel (10), and faces a third group of permanent magnets (35), wherein a fourth disk (33) is inserted with clearance in a fourth seat (34) obtained in the second driving wheel (10) in a position opposite to the third seat (46), and faces a fourth group of permanent magnets (36).

2. The auxiliary thrust system according to claim 1, wherein said at least one gear-motor unit comprises a first gear-motor unit (13, 15) driving a first driving wheel (9) and a second gear-motor unit (14, 16) driving a second driving wheel (10).

3. The auxiliary thrust system according to claim 1, wherein said at least one gear-motor unit comprises a single gear-motor unit (48, 49) driving the first driving wheel (9) and the second driving wheel (10), wherein the first driving wheel (9) and the second driving wheel (10) are arranged at opposite ends of the shaft (47) to rotate freely with respect to the shaft (47), said shaft (47) being rotated by the single gear-motor unit (48, 49).

4. The auxiliary thrust system according to any one of claims 1 to 3, wherein the electrically conductive material is aluminum.

5. Auxiliary thrust system according to any one of the preceding claims, wherein said at least one gear-motor unit (13, 15; 14, 16; 48, 49) comprises an electric motor (13, 14, 48) powered by a battery arranged on the carriage (1).

6. Auxiliary thrust system according to any one of the preceding claims, wherein said at least one gear-motor unit (13, 15; 14, 16; 48, 49) is dimensioned to generate a driving torque on the first drive wheel (9) and the second drive wheel (10) which is insufficient to move the carriage (1) without the aid of the thrust of the operator.

7. Auxiliary thrust system according to any one of the preceding claims, wherein said at least one gear-motor unit (13, 15; 14, 16; 48, 49) can be activated or deactivated by an operator acting on a handle (51) fixed to a frame (55) of the carriage (1), wherein said handle (51) is mounted to a first support (53) and a second support (54) fixed to the frame (55), said handle (51) being rotatable with respect to the first support (53) and the second support (54), wherein on at least one of the first support (53) and the second support (54) there are fixed a normally open first switch (62) and a normally open second switch (63), wherein the handle (51) is rotated in a second rotation direction (F1) by applying a traction force to the handle (51) to close the first switch (62), and rotating the handle (51) in a first rotation direction (F2) opposite to said second rotation direction (F1) by applying a pushing force to the handle (51) to close the second switch (63), said rotation being performed from a neutral position of the handle (51) in which both the first switch (62) and the second switch (63) are in an open state.

8. The auxiliary thrust system according to claim 7, wherein the first switch (62) is maintained in the closed position as long as traction is applied to the handle (51), wherein the second switch (63) is maintained in the closed position as long as thrust is applied to the handle (51).

9. Auxiliary thrust system according to claim 7 or 8, wherein a first spring (64) and a second spring (65) are mounted on the first support (53), wherein a third spring and a fourth spring are mounted on the second support (54), wherein the first spring (64), the second spring (65), the third spring and the fourth spring interact with the handle (51) to return the handle (51) to the neutral position when the application of traction or thrust to the handle (51) is stopped.

10. Auxiliary thrust system according to any one of claims 1 to 6, wherein the activation or deactivation of the at least one gear motor unit (13, 15; 14, 16; 48, 49) and the selection of the direction of rotation thereof can be carried out by an operator by means of control buttons arranged on the carriage (1) in an ergonomically suitable position for the operator, depending on the shape and structure of the carriage (1).